Effect of Interaction among N Forms and Calcium Sources on Quality and ‎Chemical Composition of Tomato(Lycopersicon esculentum)‎

A field experiment was conducted at the Experimental Farm of the Faculty of Agric. El-Mansoura Univ. During ‎season of 201‎‏3‏‎ to evaluate the effect of N-fertilization forms and different sources of calcium on chemical ‎constitutes of tomato plant and its quality (Lycopersicon esculentum) "Carmen varaity".‎
Twelve treatments were arranged in split block design with 3 replicates, which were the simple possible ‎combination between three forms of nitrogen fertilizers [ammonium sulfate, ammonium nitrate and urea] as main ‎plots, and four sources of calcium (control, calcium chloride, calcium sulfate and calcium nitrate) as sub plots. ‎Thus the total number of plots used for the season was 36 plots.‎
The results showed that; soil application of N-forms; ammonium sulfate, ammonium nitrate and urea ‎significantly affected the average values of chlorophyll (a, b and total, mg.g-1), N, P, K and Ca% in the leaves and ‎tomato quality of fruits such as N, P, K andCa%, V.C, total carbohydrates, lycobien , nitrate, acidity and TSS. ‎Except for nitrate and acidity contentsthe highest mean valuewas recorded for the plants treated with ammonium ‎sulfate,while such effect for nitrate and acidity contents were recorded for the treatments of ammonium nitrate and ‎urea, respectivelyexcept for acidity values.‎
Also, the results, indicated that the mean values of all mentioned parameters were significantly increased with ‎using different sources of calcium; calcium nitrate, calcium chloride and calcium sulfate comparing with the ‎untreated plants, and the highest values were recorded with using calcium nitrate as a source of calcium.On the ‎contrary of this trend, the average values of acidity were significantly decreased under any source of calcium ‎addition and recorded the highest value for the untreated plants.‎
Generally, the most suitable treatment which realized the highest safe yield for tomato fruits was connected ‎with the treatment of ammonium sulfate + Ca2NO3‎.